1. Field of the Invention
The present invention relates to a technique of producing a device including an impedance element provided so as to effect a series resonance. More particularly, it relates to a method of connecting connection portions such as terminals or electrodes to be electrically connected in a piezoelectric device, using conductive adhesive resin.
In general, a piezoelectric device is small-sized and has a small power loss and stable temperature characteristics, compared with a conventional resonance circuit constituted by inductance elements and capacitance elements. Accordingly, such a piezoelectric device is widely utilized in televisions, radios, communication apparatuses, or the like. In particular, piezoelectric devices are preferably used in oscillation circuits, band-pass filters, or the like, and thus they are required to have an analogically wide dynamic range.
2. Description of the Related Art
In piezoelectric devices such as piezoelectric vibrators, it is known that a phenomenon occurs in that electric characteristics of a vibrator fluctuate depending on a driving level of the vibrator in use. Conventionally, however, the cause of occurrence of such a phenomenon has been unknown. In particular, with respect to a phenomenon in that an input impedance of a vibrator fluctuates depending on a driving power thereof, it has been conceived that the phenomenon has relation to a deterioration in characteristics occurring in the case where the vibrator is applied to an oscillation circuit.
In view of this, in a prior art, a method of testing characteristics of a vibrator by changing a driving level thereof has been adopted. This method, however, poses a problem in that the testing process is troublesome and thus the number of processes becomes large.
Also, the above prior art method poses another problem in that impedance responses (i.e., frequency characteristics) of the vibrator fluctuate depending on the driving level thereof. This imposes restrictions on the manner of choice of a driving power source when the device is in use, and thus is not preferable.